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A study of sulphur xanthates in relation to their role in froth flotation of sulphide minerals

- Honeyman, Ronald

Authors: Honeyman, Ronald
Date: 1980
Type: Text , Thesis , Masters
Full Text: false
Description: Potassium alkyl xanthates are commonly used as collectors in the flotation of sulphide minerals. Much research has been directed to the formulation of mechanisms responsible for the hydrophobicity of the sulphide minerals in xanthate flotation. Alkyl dixanthogen plays an important role in this mixed-potential mechanism, and is regarded as the species which imparts hydrophobicity to the mineral surface. Winter has recently suggested that sulphur xanthates, which are chemically very similar to alkyl dixanthogen, may play a significant role in the processes rendering the sulphide minerals hydrophobic during froth flotation. The aim of this investigation was to develop techniques for the separation and identification of sulphur xanthates at very low levels of conecentration. Techniques employed were Molecular Emission Cavity Analysis Spectroscopy and High Performance Liquid Chromatography. It was possible to extract the sulpur xanthates from simulated flotation liquors, separate the individual species, and determine them to a level of 0.05 ppm in the liquor. Aklyl sulphur dixanthates were found to disproportionate in methanol solution.
Description: Masters Degree in Applied Science

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A polarographic study of lignin reactions in soda pulping liquors

- Burton, Peter

Authors: Burton, Peter
Date: 1986
Type: Text , Thesis , Masters
Full Text: false
Description: Oxidation-reduction reactions between carbohydrates, lignin and quinone additives in Pinus radiata soda pulping liquors have been investigated. A reduction peak at -0.72 V (Vs SCE) was observed using differential pulse polarography when Pinus radiata wood is heated in alkaline solution in the presence of oxygen, and has been shown to result from the oxidation of lignin structures. The results of this study indicate that the electroactive species present in Pinus radiata soda pulping liquors is an oxidation product, resulting from the formation of phenoxy radicals and /or quinone methides. Although reduction potentials for anthraquinone, carbohydrates and the electroactive lignin structure fit the general redox mechanism propsed for accelerated delignification, the species observed by polarography in this study has been shown not to be involved in the main pulping reactions due to its low concentration.
Description: Master of Applied Science

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Electrochemical studies of organic compounds in zinc electrowinning circuits

- Vawdrey, Peter

Authors: Vawdrey, Peter
Date: 1986
Type: Text , Thesis , Masters
Full Text:
Description: Most of Australia's zinc production is by the electrolytic zinc process, in which zinc is electrowon from an acid sulphate solution. The process is known to be exceptionally sensitive to the presence of trace impurities. At the Electrolytic Zinc plant (Risdon, Tasmania), isobenzofuranone (pthalide) has been detected in the electrowinning circuit, and found in higher concentrations during efficiency slumps. It was found that di-2-ethylhexyphthalate, (present in the liners and plastics used in the electrowinning circuit), is reduced to isobenzofuranone under the electrolysis conditions employed. In addition, an investigation involved a constant current electrolysis of a synthetic zinc electrolyte, as identified an additional pathway for the productionof isobenzofuranone. 2-Naphthol, added to the electrolysis circuit for current efficiency purposes, is also a major precursor of isobenzofuranone. 2-Napthol and possibly 1-nitroso-2-napthol can be oxidized to pthalic acid, either at a lead anode or via anode oxidation productions, and the phthalic acid produced can be reduced to isobenzofuranone at a zinc cathode. In addition, it was found that isobenzofurane is further reduced at the potential of zinc deposition to ultimately yield 2-methylbenzaldehyde. This compound, which has also been detected in Risdon plant electrolytes, is also toxic in the zince electrowinning circuit. The compound 2-methylabenzyl alcohol has also been detected via GLC examination of Risdon plant liquors. However, this compound was not detected in the present investigation, and thus no explanation can be offered for its presence in plant electrolytes. The toxicity of zinc electrolyte impurities on current efficiency was determined by a cyclic voltammetric technique. The results of this investigation indicate that the presence of isobenzofuranone and 2-methylbenzaldehyde can significantly lower current effciency, and the compounds phthalic acid and 2-methylbenzyl alcohol also lower efficiency.
Description: Masters Degree in Applied Science

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A differential scanning calorimetry study of some metal 2,4 pentanedionates

Authors: Murray, John
Date: 1987
Type: Text , Thesis , Masters
Full Text: false
Description: The sublimation enthalpy of beryllium (II), aluminium (III), chromium (III), iron (III), cobalt (III), nickel (II), copper (II), oxovanadium (IV) and zirconium (IV) 2,4 -pentanedionate complexes has been determined by vacuum Differential Scanning Calorimetry (DSC), subsequent to benzoic acid being proposed as calibrant for this technique. In conjunction with existing thermochemical data for these complexes, metal-ligand homolytic bond dissociation energies are calculated and are rationalized in terms of the ionic size of the coordinated meta and the crystal field stabilization energies for the complex. Old and new methods for the determination of sublimation enthalpy are reviewed and the present data collectively reveal the versatility and precision of DSC fort the direct determination of sublimation enthalpies of metal complexes. The new sublimation enthalpy data presented for metal 2-4- pentanedionate complexes effectively ends the controversy associated with the previously reported corresponding data/
Description: Master of Applied Science

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Seated working posture : a research thesis with experimental methodology and literature review

- Nelson, David

Authors: Nelson, David
Date: 1990
Type: Text , Thesis , Masters
Full Text:
Description: Masters Degree in Applied Science
Description: Much has been written about seated working posture - particularly in the late 19th and early 20th centuries, and the furniture associated with achieving what is commonly referred to as the "German Square" postural geometry (after Mandal, 1974). The physical sciences aspects of chair, desk and associated furniture ancillary to the task required of the seated worker, have been described in the scientific literature and the standards and guideline publications of the authorities of many countries of the western world. The most important contribution of multi-adjustable furniture to the reduction of postural discomfort and musculo-skeletal complaints is recognised. As a result a variety of standards and guidelines concerning some of these aspects exists in countries such as the United Kingdom, Canada, United States of America, Germany, Australia and the Scandinavian countries. The International Organisation for Standardisation published document TC136/SC7 in 1978, consolidating such existing standards. Less emphasis has been placed on the interface of the information exchange and the comfort, performance and preferences of the seated worker; ie., the practically, the comfort and the intrinsic safety of the working posture prescribed by the model established by the many standards. Existing specifications and guidelines differ in their orientation towards operator performance and comfort of the operator, in as much as some purport to be "furniture standards", for example C.E.N, Comite European de Normalisation, Paris, 1980, while others purport to be "postural standards", for example, International Organisation for Standardisation document TC 136/SC7 (1978). The standards are uniform in matters of upright trunk and 90° upper and lower limb geometry, but are divided in the lineal dimensions applied to eye height above the floor, shoulder acromion to home row of keys (or pen-grip position of the dominant hand and fingers), and eye distance to copy.

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Lifting devices used by hospital staff; their relationship to the handling of patients

- Lean, Leonard

Authors: Lean, Leonard
Date: 1991
Type: Text , Thesis , Masters
Full Text: false
Description: This paper investigates the utilisation of lifting devices by hospital staff, in relation-ship to the handling of patients and the reasons for this. A survey was conducted at Flinders Medical Centre, Adelaide during June and July 1989 using a questionnaire which returned 54% (n=110) completed returns. The results showed a lack of available lifting devices; 16.4% (n=18) of health care respondents had no lifting devices available in their work area while 14.5% (n=16) of respondents had only one lifting device. Where lifting devices were available, 63.6% (n=70) of respondents used the lifting devices less than three times in the week prior to the survey. 24.6% (n=27) of respondent health care workers were of the opinion that lifting devices were not very appropriate for patient handling tasks and 12.7% (n=14) of respondents found the devices difficult to use. 22.7% (n=25) of respondents indicated insufficient room for the use of the devices. 19.1% (n=21) of respondents consider the floor plan layout in which they to be utilised obstructive. 24.5% (n=27) were of respondents found that the lifting devices were not very mobile. 24.6% (n=27) of respondents considered that the setting-up time of the lifting devices took too long and 18.2% (n=20) were of the opinion that the devices were located too far away from the workplace for quick and convenient access. Strong emphasis in the literature review is placed on Common and Statute Law of the employer's "Duty of Care" to the health care workers. The main recommendation is that users need to have input into the design of the equipment. Also, user require initial training and require on-going refresher training in the use of lifting devices for patients. Supervision of users of lifitng devices is essential.
Description: Thesis (Master of Applied Science )

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A cost analysis of accidents and injuries in the open cut coalmining industry

Authors: Esson, Ken
Date: 1992
Type: Text , Thesis , Masters
Full Text: false
Description: Following a study of back injuries in the Queensland Coal Industry, there arose several questions that needed further research. One of these was the cost of accident and injuries, and the impact of this cost would have on an organisation. The project's research involved a comprehensive study of literature pertaining to the cost of accidents and injuries. This included both insured and uninsured costs. The following four classifications of accidents were researched; first aid treatments; first aid doctor treatments; lost time injury cases; and equipment accident damage cases. A coal mine was selected for the pilot study and, data was collected on the four classifications over a complete year. This means a year that has no out standing accident cases or liablilities. The research was then considered to determine its support for the acceptance or rejection of the hypothesis whic postulates that the current methods used to analyse the cost of accidents or injuries in the coal mining industry are inadequate. As a result of the above condsiderations, a number of key points are put forward in support of the acceptance of the hypothesis. The research established costs both insured and uninsured for the four classifications under review. Then a calculation of a weighted ratio of uninsured costs was made. The paper concludes by making certain recommendations and supporting the need for further research into accident costing within the coal mining fraternity.
Description: Masters in Applied Science in Occupational Health and Safety

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